MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY Takahiro Watari DEVELOPMENT OF AN APPROPRIATE TREATMENT SYSTEM FOR NATURAL RUBBER PROCESSING WASTEWATER TREATMENT CHEMICAL ENGINEERING DISSERTATION Hanoi – 2022 MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY Takahiro Watari DEVELOPMENT OF AN APPROPRIATE TREATMENT SYSTEM FOR NATURAL RUBBER PROCESSING WASTEWATER TREATMENT Major: CHEMICAL ENGINEERING Code No.: NCS16091 CHEMICAL ENGINEERING DISSERTATION SUPERVISORS: 1. Nguyen Minh Tan 2. Takashi Yamaguchi Hanoi – 2022 ACKNOWLEDGMENT Firstly, I would like to thank the Professors and Staff in the Ph. program, the officers in the Department of Education, Hanoi University of Science and Technology.
Thank you for all the guidance and support you have made for me while I have fulfilled the dissertation. Working with colleagues in the Department of Chemical Engineering has been a privilege. I would like to thank you from the bottom of my heart for your constant encouragement. Finally, I am so glad to have a supervisor like Assoc.
Nguyen Minh Tan. Ever since I have started to work under your supervision, I have learned a lot which really helps me to become a better person. Thank you! You are the best supervisor ever. I hope to receive some words of encouragement and full support from the readers in order to make my Ph.
Hanoi, …/…/… Author of the dissertation Takahiro Watari i DECLARATION I hereby certify that the dissertation "Development of an appropriate treatment for industrial rubber industrial wastewater treatment" is my own research project. The data and results stated in the doctoral dissertation are honest. I hereby declare that the information cited in the doctoral dissertation has been fully originated. Hanoi,…/…/… ON BEHALF OF SUPERVISORS Author Assoc.
Nguyen Minh Tan Takahiro Watari ii CONTENTS ACKNOWLEDGMENT. iii FIGURE LIST. iv TABLE LIST. 2 Current Problem and its solution.
State of the art .1 Natural rubber processing process .2 Natural rubber processing wastewater. Current treatment technology for natural rubber processing wastewater .1 Biological aerobic and anaerobic pond .2 Upflow anaerobic sludge blanket reactor.3 Anaerobic baffled reactor .4 Activated sludge process .5 Swim bed tank .6 Down flow hanging sponge reactor .7 Dissolved air floatation .9 Combination of treatment systems for natural rubber processing wastewater .3 Industrial wastewater treatment process .1 Characteristics of anaerobic wastewater treatment and the degradation pathway of anaerobic digestion .2 Anaerobic industrial wastewater treatment technology .3 Characteristics of aerobic wastewater treatment and the degradation .4 Greenhouse gas emissions from the wastewater treatment system. Material and methods .1 Greenhouse gases collection and analysis .2 Laboratory UASB-DHS system .2 System description and operational conditions .3 Laboratory scale ABR system .1 Raw natural rubber processing wastewater .2 System description and operational conditions .4 Pilot UASB-DHS system .1 Potential of hydrogen .3 Oxidation-reduction potential .4 Chemical oxygen demand .5 Biochemical oxygen demand .8 Ammonia, nitrite, and nitrate .9 Volatile fatty acid .10 Biogas production and composition. Results and Discussions .1 Characterization of a current wastewater treatment system .2 Development concept of a laboratory scale UASB-DHS system for natural rubber processing wastewater treatment .3 Development concept of a laboratory scale ABR experiment .1 Process performance of ABR .2 Determinates profiles inside the ABR .4 Development concept of a pilot scale UASB-DHS system experiment for treatment of natural rubber processing wastewater .2 Nitrogen removal and greenhouse gas emissions .3 Performance comparison of ABR-UASB-DHS system and existing treatment system.5 Design for full-scale UASB-DHS system for natural rubber processing wastewater in Vietnam .1 Reactor design for natural rubber processing wastewater .1 Pre-treatment process for UASB reactor .2 Calculation of Energy consumption and generation for the operation of the UASB-DHS system .1 Energy consumption of UASB-DHS system .2 Energy production of UASB-DHS system.
80 Recommendation for future study. 91 v FIGURE LIST Figure 1.1 Top natural rubber produced countries over the world in 2014 [3].2 Natural rubber harvested area and production in Vietnam [2] .3 Natural rubber production area in Vietnam [2].4 Natural rubber manufacturing process [5].5 Schematic diagram of coagulation process [5] .6 Full-scale biological pond in Vietnam.7 Schematic diagram of UASB reactor.8 Various reactor configurations of ABR [16] .9 Basic water flow in conventional activated sludge.10 Principle of downflow hanging sponge reactor and full-scale DHS in India.11 Development history from DHS G1 to DHS G6 [30].12 Anaerobic digestion scheme of organic compounds.13 Aerobic biological degradation pathway.1 Schematic diagram of open-type anaerobic system.2 Gas sampling system used in this study.3 (A) Thanh Hoa Rubber Factory, (B) Coagulation process in natural rubber sheet producing process.4 Schematic diagram of the baffled reactor (BR), upflow anaerobic sludge blanket (UASB), and downflow hanging sponge (DHS) combined system.5 Protocol for preparation of natural rubber processing wastewater iv following actual factory methods.6 Schematic diagram of anaerobic baffled reactor.7 Schematic and photo of the pilot scale ABR-UASB-ST-DHS system.1 Biogas composition of compartments 28, 33, and 56.2 Methane gas emission rate and COD concentration of each compartment.3 COD mass balance in the OAS .4 Nitrous oxide rate and ammonia concentration in each compartment.5 Composition of emitted GHGs from near the influent part, the center part, and the effluent part of the OAS.6 Time course of pH and temperature during the operation periods.7 Time course of (a) total COD, (b) soluble COD, (c) TSS, (d) VSS, and (e) TN during the operation periods.8 COD mass balance of the influent, BR effluent, and UASB effluent.9 Time course of (A) Total COD and (B) TSS concentrations through phase 1 to phase 3 .10 Soluble COD, acetate, and propionate concentrations in ABR on (A) 103 day and (B) 199 day .11 Accumulation of rubber particular in feed pipe and photo of wastewaters.12 Time course of (A) Total COD removal efficiency and organic loading rate of UASB reactor, (B) Total BOD removal efficiency.13 (A) Total nitrogen and (B) ammonia removal efficiency of the total system and DHS reactor during phase 1 to phase 4. 91 v TABLE LIST Table 1.1 Characteristics of natural rubber processing wastewater in Vietnam.2 National technical regulation on the effluent of natural rubber processing industry in Vietnam.3 Type of treatment process applied in Vietnam [4].4 Application of UASB reactor for natural rubber processing wastewater treatment.5 Comparison of technologies used for natural rubber processing wastewater treatment.6 Benefits of the anaerobic treatment process.7 Application of anaerobic technology to industrial wastewater [33].8 Global warming potential of GHG.1 Water quality of natural rubber processing wastewater obtained from a natural rubber sheet producing factory in Thanh Hoa Province.2 Summary of the initial operational conditions for the two operating phases.3 Operational conditions for anaerobic baffled reactor.4 Initial operational conditions through phases 1 to 4.1 Present treatment system flow of a local natural rubber processing factory.2 Water quality in each sampling point at a local natural rubber processing wastewater in Vietnam.3 Summary of process performance of the treatment system.4 Summary of the process parameters of the system during entire experimental period.5 Biogas production and compositions of the UASB reactor.6 Nitrogen concentrations (mg-N·L-1) in the proposed system.7 Characteristics of natural rubber processing wastewater in Thailand, Malaysia, and Vietnam.8 Process performance of the existing treatment system for treating natural rubber processing wastewater.9 Water quality of natural rubber processing wastewater for simulation. 75 vii Abbreviations words list ABR Aerobic baffled reactor BOD Biochemical oxygen demand CL Concentrated latex COD Chemical oxygen demand DAF Dissolved air flotation DHS Downflow hanging sponge DO Dissolved oxygen GC Gas chromatograph GHG Greenhouse gas GRABBA Granular-bed anaerobic baffled reactor GSS Gas-liquid-solids separation GWP Global warming potential HRT Hydraulic retention times MBR Membrane bioreactor OAS Open-type anaerobic system OLR Organic loading rate ORP Oxidation-reduction potential pH Potential of hydrogen PVC Polyvinyl chloride RSS Ribbed smoked sheet SRB Sulfate-reducing bacteria ST Settling tank SVR Standard Vietnamese Rubber TN Total nitrogen TSR Technically specified rubber TSS Total suspended solids UASB Upflow anaerobic sludge blanket VFA Volatile fatty acids VSS Volatile suspended solids viii Introduction Natural rubber is one of the most valuable agricultural products in Southeast Asian countries.
Vietnam is the 3rd largest natural rubber-producing country, and natural rubber production in Vietnam is increasing each year. However, the natural rubber industry discharges large amounts of wastewater containing high concentrations of organic compounds, nitrogen, and other contaminants from several manufacturing processes such as coagulation, centrifugation, lamination, washing, and drying. The natural rubber processing factories in Southeast Asian countries commonly use a combined anaerobic-aerobic lagoon system for treating natural rubber processing wastewater because of the low installation costs. The existing treatment systems have been demonstrated to achieve a high chemical oxygen demand (COD) removal efficiency of 65 to 90% with easy operational methods.
However, they require a large area for the lagoon, high operating costs (especially for surface aeration), and long hydraulic retention times (HRTs). However, the effluent water quality of these existing treatment systems needs to be improved to conform to the established discharge standards. An upflow anaerobic sludge blanket (UASB) reactor is one of the most promising systems for the treatment of different types of industrial wastewater because of its high organic loading rate (OLR), low operational costs, and energy recovery in the form of methane. Previous studies have reported the application of the UASB reactor for the treatment of natural rubber processing wastewater.
However, it was determined that natural rubber particles remaining in the wastewater had a negative effect on the anaerobic biological process. Therefore, the development of a pre-treatment system to remove the remaining natural rubber particles is essential. Moreover, when a UASB reactor is used to treat high-strength industrial wastewater, the effluent still contains high concentrations of organic compounds and nutrients. Thus, an aerobic treatment system is typically applied as a post-treatment to remove residual organic matter and meet effluent standards.
A downflow hanging sponge (DHS) reactor is one of the most effective aerobic 1 treatment systems applied as a post-treatment with the UASB reactor to treat different types of industrial wastewater. Objective Current wastewater treatment systems used to treat natural rubber processing wastewater in Vietnam consume a large amount of electrical energy and have a large negative impact on the environment. In this study, we characterized the process performance (e., water quality and biogas emission) of the current wastewater treatment system and developed an energy-recovery type advanced wastewater treatment system to reduce greenhouse gas (GHG) emissions and improve the effluent quality resulting from the treatment of natural rubber processing wastewater. Tasks (Scientific and practical meanings) 1) Characterization of the current wastewater treatment system used to treat natural rubber processing wastewater in Vietnam To investigate the current situation of natural rubber processing wastewater treatment in Vietnam, field, and journal paper surveys were conducted.
Moreover, GHG emissions from an existing anaerobic lagoon were measured to determine the environmental impact on global warming. 2) Development of an energy-recovery type wastewater treatment system The UASB-DHS system has been applied to treat domestic sewage and several types of wastewater. In addition, the UASB-DHS system was successfully applied in Thailand to treat natural rubber processing wastewater, which contained a high concentration of sulfuric acid. In this study, we examined the application of the UASB-DHS system for treating natural rubber processing wastewater in Vietnam and evaluated its process performance at the laboratory scale and in a pilot-scale experiment.
2 3) Establishment of an optimal treatment system for natural rubber processing wastewater treatment in Vietnam Following these results, we established an optimal treatment system for natural rubber processing wastewater treatment in Vietnam. The discharge amount of industrial wastewater in Vietnam is expected to increase each year. A conventional activated sludge process is usually applied to treat industrial wastewater in developed countries, but the installation, operation, and maintenance of this type of system is very expensive. The UASB-DHS system we developed is known to be an energy-recovery and energy-saving wastewater treatment system and has been applied to several types of wastewater.
If the application of the UASB-DHS system to natural rubber processing wastewater in Vietnam is successful, it could reduce operational costs and GHG emissions and improve the effluent quality.